When a speech, a lecture, or the like is addressed to a large audience in a lecture hall or a classroom, conventionally a speaker or lecturer provides the content of a speech, a lecture, or the like, directly to the audience—viewers of the content. In such a case, the speaker or the lecturer is able to flexibly change the content while checking a degree of fatigue of the audience, and the audience is able to listen to the speech, the lecture, or the like seated without effectively being interrupted from the outside during a session of the above.
On the other hand, in recent years, more and more providers and audience of content at remote places enjoy the benefit of, for example, E-learning or on-line video delivery of lecture content. In this case, since the provider and the audience of the content are at different places, the content provider may be unable to recognize states of the audience. More specifically, it is difficult for the content provider, for example, to flexibly adjust the content through checking whether the audience is surely receiving the content, i.e., through checking, for example, whether there is an individual who dozes and fails to obtain an important point or whether the lecture is audible to even the audience in the back of a lecture room.
On the audience side, concentration on the content may be disturbed when, for example, there is a telephone call when the content is reproduced whilst being seated. It is difficult to adjust the content to induce the viewers to concentrate on a lecture and not to miss important points of the content in accordance with the degree of the content importance.
Systems for monitoring situations of audience in respective scenes of content delivery have been conventionally proposed. For example, Japanese Patent Application Laid-Open No. 2005-56205 and Japanese Patent Application Laid-Open No. 2007-82022 propose such systems.